Posts Tagged‘abiogenesis’

DNA Can Survive in Space, Re-Entry into Atmosphere.

There’s a few competing theories around how life came to be on our planet. One of them is the theory of abiogenesis, the idea that the building blocks of life assembled themselves from the primordial soup of the Earth to eventually give rise to life as we know it today. As an origin for all life it makes sense as it had to come from somewhere although whether or not it was how life came to be here is still up for question. Indeed the competing theory for how life originated here comes in the form of panspermia, the notion that our world was somehow seeded with life from planets elsewhere. Whilst it’s likely impossible to prove either of these theories they do lead to some interesting ¬†areas of scientific research, the latter of which just bore some interesting fruit.

DNA HelixOne of the biggest questions with the idea of panspermia is whether or not the building blocks of life could survive in the harsh climate of space. We have known for some time that simple forms of life are able to tolerate the conditions of space for what seems like an eternity but given the time frames involved it’s far more likely that their genetic components would be the only things that would survive the long journey through space. Whether or not DNA could survive some of the most harsh conditions, like plunging back into the Earth’s atmosphere at re-entry speeds, is a question that researchers at the University of Zurich attempted to answer.

The results are quite intriguing, showing that the DNA molecules (which were applied to the outside of the craft with no shielding to speak of) was still viable upon returning to Earth. Whilst it’s far from a long duration spaceflight, the TEXUS launch system is a sub-orbital platform, it does show that DNA is very resilient to the harsh conditions experienced in space, lending credence to the idea that our Earth may have been seeded with genetic material of alien origin. Just how that material would have ended up finding it’s way here though is another question entirely, although it is an interesting one.

Genetic material lacks the capability to launch itself into space and so the only way it finds its way off a planet (bar ours) is to hitch a ride on a cataclysmic event. Large asteroids that impact a planet shoot up all manner of ejecta, some with enough energy to escape their planet’s gravity entirely. It’s a rare event, to be sure, however it’s happened often enough that we’ve got numerous bits of Mars scattered on Earth’s surface¬†and likely bits of other planets that we don’t yet know about. If just a few of these kinds of asteroids hit Earth at the right time our origins of life might lie far beyond our own planet, or possible even our own galaxy.

It never ceases to amaze me just how resilient the building blocks of life are, being able to survive the harshest conditions and still remain viable. This then leads onto us finding life in all sorts of weird places, ones where you’d think it’d be impossible for anything to survive. I honestly can’t wait for the day when we find life on another planet, even if its microbes, as it will tell us so much about who we are and where we came from.

 

Antarctica, Europa and Life Not as we Know it.

Life is a tricky thing to get right. As far as we know right now we’re a completely unique in this universe and the conditions that led to us being here are both mysterious and endlessly intriguing. Whilst I won’t dive into the debate on science vs religion here (I’ve already done that) my own personal views are ones of abiogenesis, or more simply the idea that the complex life that we know and love today arose from a long chain of events that started with just the basic elements of the universe. Whilst there’s still a lack of consensus around the actual mechanisms that would have led to this happening the basic idea remains the same.

This is mostly due to the lack of another point of data, I.E. us encountering life that arose on another planet. So instead we start looking around our own earth to find examples of how life got started and where it exists. We’re discovering more and more that environments that we thought were completely incompatible with life are actually teaming with creatures that seem almost impossible to us. From complex curiosities like the Yeti Crab and the Flashlight Fish to bacteria that thrive on the heat radiated from black smokers it seems that once conditions are favourable to life you’ll end up finding it pretty much anywhere.

Still there are some places you just don’t expect to find life, like 185 meters below an ice sheet:

Researchers in Antarctica got a surprise visit from a creature in a borehole 185 meters (600 feet) below the Antarctic ice, where there is usually no light. A Lyssianasid amphipod, a shrimp-like creature can be seen swimming in this video. A NASA team had lowered a small video camera to get the first-ever photograph of the underside of an ice shelf when the curious little 7 cm (3- inch) shrimp stopped by to check out the equipment. Scientists say this could challenge the idea of where and how forms of life can survive. Anyone else thinking Europa?

To say that little shrimp was completely unexpected would be putting it lightly as for all we knew there was absolutely nothing down there capable of supporting life any larger than simple bacteria. They also found what appears to be the tentacle of a jellyfish tangle around the cord of the camera suggesting there’s not only life but also some amount of diversity down there. So whilst this might be cool and all why is everyone asking about Europa?

For those of you not in the know Europa is a moon of the planet Jupiter and is only a bit smaller than our very own Moon. It’s quite a striking thing to look at as it’s surface looks like a round ice cube that’s covered in dust, very different to our closest neighbour who’s an even shade of dull gray. When we get up and close to it we see it’s covered in these long lines which look scarily similar to ice sheets on earth. As it turns out Europa’s crust is actually a solid layer of ice that’s a few kilometers thick and under that is an internal ocean that, as our best guess goes, is tens of kilometers deep. The lines on the surface are cracks that opened up to the internal ocean below where upon water from below swelled up to fill the gap.

What the scientists’ unexpected visitor tells us is that there is the possibility for complex life to evolve in places where light cannot reach it, and that means that there’s a chance that life evolved in the sea under Europa.

You may be wondering how life could evolve in a place that’s covered by kilometers of ice in a frigid sea so far from the sun. Well as it turns out thanks to its giant parent planet and slightly non-circular orbit Europa is constantly being squeezed and pulled every time it completes one round trip. This has the effect of creating an extreme amount of internal heat that not only serves to keep the internal ocean liquid but could also serve to generate the volcanism that some theories believe is required to create life. Out of all the other places in the solar system this is probably the only other place where life could potentially exist based on the evidence we’ve gathered here on earth.

It’s discoveries like this that get me all excited about the infinite possibilities of the universe. Whilst there’s no evidence that there are any other intelligent life forms out there the evidence is getting stronger and stronger that it’s there, we just have to go and find it. I know that one day we’ll send a probe to Europa to see what is really under that thick ice blanket and should we find life there you can bet your bottom dollar that it will change how we view ourselves and our place in the universe forever.